The present invention is directed to electrical memory devices. By way of example and not by way of limitation, the present invention is advantageously employed with EEPROM (Electronically Erasable Programmable Read Only Memory) devices, apparatuses or products.
Electrical memory devices, such as EEPROMs, are commonly used to store data in digital form. In mixed signal circuitry (e.g., circuitry containing digital circuit sections and analog circuit sections) such electrical memory elements or storage elements may be used to store information that is used to trim analog circuits or to calibrate sensor elements interfacing with a circuit. The electrical memory devices are therefore critical to the proper operation of circuits containing them, including digital circuits, analog circuits and mixed circuits so that electrical memory devices must reliably retain their programmed states over the lifetime of a product containing them.
There is a need for a method by which a manufacturer can verify that an electrical memory device is configured to properly retain a programmed state before shipping the device to a customer.
Because die space is such a premium in today's smaller, faster products, it is preferred that such a method for verification minimally affect die area for its implementation and practice.